On 01/12/14 09:08, Robin Hill wrote:

If it is doable (see comment above), it'll be simpler to just
partition the disks to the final size (or skip partitioning at all)
- md will quite happily accept larger devices added to an array
(though it doesn't use the extra space). Otherwise, your initial
steps are correct - though if you have a spare bay (or even a
USB/SATA adapter), you can add the drive as a spare and then use
"mdadm --replace" (you may need a newer version of mdadm for this)
command to flag one of the existing array members for replacement.
This will do a direct copy of the data from the existing disk to
the new one and is quicker (and safer) than fail/add.

I upgraded a (raid 1) system by just adding the new, larger, disk. I
think I swapped a 500Gb for a 1TB, so replaced my 400Gb partitions
with 900Gb partitions. I then grew the array, followed by growing the
partition. Worked fine.

Cheers,
Wol